Out of Africa?

Has anyone else wondered why a story occurring in Africa contains none of the typical devices used in movies of the time to indicate an African location? It is devoid of the clichés familiar from dozens of films of the jungle adventure variety: no menacing jungle drums; no reels of stock footage showing wildlife and ‘natives’ dancing; no exotic, voodoo-type ceremonies; no sound-stage jungle sets. In other words, Zombies of Mora Tau has none of the ‘local color’ splashed through similar themed films from the time such as Voodoo Woman or The Disembodied.
More remarkable is the absence of any black characters. Even the servants – a minor role widely employed for mixing a couple of black faces into a largely white cast – are all white, from Sam the chauffeur, to Margaret the briefly appearing maid, to “Sam's men,” who bury Johnson the sailor and feed the fire in front of the zombie crypt. The lack of Africa seems so thorough I would think it intentional, if I didn’t know better...which I don’t.